Unmanned aerial vehicle trajectory optimization method based on Bezier curve and flight corridor

Abstract

The invention provides an unmanned aerial vehicle trajectory optimization method based on a Bezier curve and a flight corridor. The method comprises the following steps of map data acquisition and processing, target setting and path planning, Bezier curve generation and optimization, flight corridor design, path verification and adjustment, and real-time path tracking and control. According to the method, the Bezier curve and the flight corridor are combined, so that the accuracy, the smoothness and the adjustability of the flight path of the unmanned aerial vehicle are improved, and the efficiency and the safety in the flight process are optimized.

Description

Technical Field

[0001] The invention relates to the technical field of unmanned aerial vehicle path planning, and in particular to a method for optimizing the trajectory of an unmanned aerial vehicle based on Bezier curves and flight corridors. Background Art

[0002] In modern drone technology, flight path planning and optimization are crucial. Traditional methods of connecting paths with straight lines or simple curves have problems of low efficiency and insufficient safety. These methods are particularly limited when complex track adjustments or obstacle avoidance are required. In order to overcome these challenges, researchers have begun to explore more advanced path planning methods in recent years, including the use of the mathematical model of Bezier curves. Bezier curves are known for their smoothness, continuity, and flexibility. They can accurately describe the curvature changes in the flight path and meet the needs of different application scenarios by adjusting control points. Combined with the concept of flight corridors, the pre-designed and optimized flight area range can effectively improve the safety and efficiency of drone flights. This combination of technologies is not only applicable to the military and civil aviation fields, but also shows broad application prospects in various complex environments and terrain conditions. Summary of the invention

[0003] In order to solve the problems of the prior art, the present invention provides a UAV trajectory optimization method based on Bezier curves and flight corridors. By combining Bezier curves and flight corridors, the accuracy, smoothness and adjustability of the UAV flight path are improved, thereby optimizing the efficiency and safety during the flight process.

[0004] The present invention provides a UAV trajectory optimization method based on Bezier curves and flight corridors, comprising the following steps:

[0005] 1) Map data acquisition and processing: Acquire map data of the flight area, process the map data, and establish a digital elevation model and a 3D space model;

[0006] 2) Target setting and path planning: Determine the starting point and end point of the drone, as well as possible intermediate target points or areas, use the Bezier curve algorithm for path planning, and design a curved path that meets flight safety and efficiency according to the requirements of the flight mission;

[0007] 3) Bezier curve generation and optimization: Generate the control points of the Bezier curve based on the path planning results. By adjusting the positions of the control points and the parameters of the curve, the shape and flight characteristics of the curve are optimized to ensure that the UAV can fly smoothly in the predetermined area.

[0008] 4) Flight corridor design: Based on map data and path planning results, design the flight corridor, i.e. the predetermined flight channel;

[0009] 5) Path verification and adjustment: Verify and simulate the generated flight paths and corridors, adjust the design of Bezier curves and flight corridors according to the simulation results, optimize the flight paths, and ensure safety and efficiency in various flight situations;

[0010] 6) Real-time path tracking and control: The optimized flight path is input into the UAV’s flight control system.

[0011] Further improvement, the map data in step 1) includes terrain height, obstacle location, and flight restricted area information.

[0012] Further improvement, in the process of path planning using the Bezier curve algorithm in step 2), the local trajectory is represented by a Bezier curve, the Bezier curve is represented by a Bernstein polynomial, and the general polynomial is transformed into a Bernstein polynomial form. The basis function of the Bernstein polynomial is

[0013]

[0014] Where n is the highest order;

[0015] A certain dimension of the trajectory of a quadrotor drone based on the seventh-order Bezier curve can be expressed as:

[0016]

[0017] We choose to generate trajectories by setting the objective function to minimize Snap. For a certain dimension, we write the minimized objective function as:

[0018]

[0019] Using the derivative properties of the Bezier curve, the control points of each order of the UAV are defined. represents the l-th order derivative of the ith control point of the k-th trajectory of dimension λ, then It can be expressed as:

[0020]

[0021] Boundary constraints and continuity constraints are written in the form of equality constraints, safety constraints and multi-order dynamic feasibility constraints are written in the form of inequality constraints, and the trajectory generation problem is formulated as:

[0022]

[0023] A eq c=b eq

[0024] st A ie c≤b ie

[0025] c k ∈Ω k ,k=1,2,…,m

[0026] Where c is the polynomial coefficient to be solved, which is a one-dimensional column vector composed of the polynomial coefficients of k segments of trajectory, and is also the control point of the UAV trajectory. k is the n control points in the flight corridor where the kth trajectory is located These control points are denoted as Ω k , which is solved in finite time using a convex solver.

[0027] As a further improvement, in the flight corridor design described in step 4), factors of flight safety and environmental protection are taken into consideration, and the location and width of the flight corridor are marked on the map.

[0028] As a further improvement, in the real-time path tracking and control described in step 6), the position and flight parameters of the UAV during flight are monitored in real time to ensure the accuracy and stability of the path, and the flight path is adjusted according to real-time environmental changes to ensure that the UAV can dynamically adapt to the needs of the flight mission.

[0029] The beneficial effects of the present invention are:

[0030] (1) Enhanced safety: The potential risk of collision with ground obstacles is reduced, and the safe flight path of the UAV is ensured by optimizing the trajectory.

[0031] (2) Efficiency improvement: By using Bezier curve optimization, a smoother and more efficient flight path is achieved, reducing unnecessary turns and acceleration and deceleration during flight.

[0032] (3) Reduced energy consumption: Optimized trajectory design can reduce energy consumption, thereby extending the flight time of the UAV and improving flight efficiency.

[0033] (4) Precise mission execution: The UAV’s flight path can be precisely controlled to ensure that the mission is performed in the target area in the best manner, thus improving the quality and accuracy of mission completion.

[0034] (5) Route planning optimization: The design of flight corridors can more effectively plan long-distance routes, reduce flight resistance along the path, and improve the overall efficiency of the flight.

[0035] In summary, the UAV trajectory optimization method based on Bezier curves and flight corridors can not only improve flight safety and efficiency, but also reduce energy consumption and improve the accuracy of mission execution. It is an important technical innovation direction in future UAV applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 Flowchart for drone trajectory optimization. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The invention aims to improve the accuracy, smoothness and adjustability of the UAV flight path by combining Bezier curves and flight corridors, thereby optimizing the efficiency and safety during the flight process. The local trajectory is represented by a Bezier curve. The Bezier curve can be represented by a Bernstein polynomial. Bernstein polynomials are a special type of polynomial that can be converted into Bernstein polynomial form by transforming general polynomials. The basis function of Bernstein polynomials is

[0040]

[0041] Where n is the highest order. The polynomial composed of Bernstein basis functions is called a Bezier curve. For the Bezier curve, the control points can be regarded as the weights of the basis functions, and the basis functions can also be regarded as the weights of the control points. Since the time parameter in the Bezier curve is in a fixed interval [0,1], for each segment of the trajectory, we need a scaling factor s to map the time t to this interval. Combined with the derivation of the track model based on differential flatness characteristics, a certain dimension in the track of a quadrotor drone based on the seventh-order Bezier curve can be expressed as:

[0042]

[0043] We choose to generate trajectories by setting the objective function to minimize Snap. The minimized objective function for a certain dimension can be written as:

[0044]

[0045] Using the derivative properties of the Bezier curve, the control points of each order of the UAV are defined. represents the l-th order derivative of the ith control point of the k-th trajectory of dimension λ, then It can be expressed as:

[0046]

[0047] Boundary constraints and continuity constraints can be written as equality constraints, safety constraints and multi-order dynamic feasibility constraints can be written as inequality constraints, and the trajectory generation problem can be expressed as:

[0048]

[0049] A eq c=b eq

[0050] st A ie c≤b ie

[0051] c k ∈Ω k ,k=1,2,…,m

[0052] Where c is the polynomial coefficient to be solved, which is a one-dimensional column vector composed of the polynomial coefficients of k segments of trajectory, and is also the control point of the UAV trajectory. k is the n control points in the flight corridor where the kth trajectory is located These control points are denoted as Ω k At the same time, according to the design of the flight corridor and the convex hull of the Bezier curve, the constraint area is also a convex area, so this is a convex quadratic programming problem, which can be directly solved in a finite time using a convex solver.

[0053] like Figure 1 As shown, the specific process is as follows:

[0054] Step 1: Map data acquisition and processing:

[0055] Obtain map data of the flight area, including terrain height, obstacle location, flight restriction area, etc. Process the map data to build a digital elevation model (DEM) and 3D spatial model for subsequent path planning and optimization.

[0056] Step 2: Goal setting and path planning:

[0057] Determine the starting and ending points of the drone, as well as possible intermediate target points or areas. Use the Bezier curve algorithm for path planning, and design a curved path that meets flight safety and efficiency according to the requirements of the flight mission.

[0058] Step 3 Bezier curve generation and optimization:

[0059] Based on the path planning results, the control points of the Bezier curve are generated. By adjusting the positions of the control points and the parameters of the curve, the shape and flight characteristics of the curve are optimized to ensure that the drone can fly smoothly in the predetermined area.

[0060] Step 4 Flight corridor design:

[0061] Based on the map data and path planning results, the flight corridor, i.e. the predetermined flight channel, is designed. Taking into account flight safety and environmental protection factors, the location and width of the flight corridor are marked on the map.

[0062] Step 5: Path verification and adjustment:

[0063] Verify and simulate the generated flight paths and corridors. Adjust the design of Bezier curves and flight corridors based on the simulation results to optimize the flight paths and ensure safety and efficiency in various flight situations.

[0064] Step 6 Real-time path tracking and control:

[0065] Input the optimized flight path into the UAV’s flight control system. Monitor the UAV’s position and flight parameters in real time during flight to ensure the accuracy and stability of the path. Adjust the flight path based on real-time environmental changes to ensure that the UAV can dynamically adapt to the needs of the flight mission.

[0066] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, the above is only a preferred embodiment of the present invention. Since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field is within the technical scope disclosed by the present invention. For ordinary technicians in the technical field, changes or replacements that can be easily thought of should be covered within the protection scope of the present invention without departing from the principle of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A UAV trajectory optimization method based on Bezier curve and flight corridor, characterized in that The following steps are involved: 1) Map data acquisition and processing: Acquire map data of the flight area, process the map data, and establish a digital elevation model and a 3D space model; 2) Target setting and path planning: Determine the starting point and end point of the drone, as well as possible intermediate target points or areas, use the Bezier curve algorithm for path planning, and design a curved path that meets flight safety and efficiency according to the requirements of the flight mission; 3) Bezier curve generation and optimization: Generate the control points of the Bezier curve based on the path planning results. By adjusting the positions of the control points and the parameters of the curve, the shape and flight characteristics of the curve are optimized to ensure that the UAV can fly smoothly in the predetermined area. 4) Flight corridor design: Based on map data and path planning results, design the flight corridor, i.e. the predetermined flight channel; 5) Path verification and adjustment: Verify and simulate the generated flight paths and corridors, adjust the design of Bezier curves and flight corridors according to the simulation results, optimize the flight paths, and ensure safety and efficiency in various flight situations; 6) Real-time path tracking and control: The optimized flight path is input into the UAV’s flight control system.

2. The method for optimizing the trajectory of a UAV based on Bezier curves and flight corridors according to claim 1, characterized in that: Step 1) The map data includes terrain height, obstacle location, and flight restriction area information.

3. The method for optimizing the trajectory of an unmanned aerial vehicle based on Bezier curves and flight corridors according to claim 1, characterized in that: In the process of path planning using the Bezier curve algorithm in step 2), the local trajectory is represented by a Bezier curve, and the Bezier curve is represented by a Bernstein polynomial. The general polynomial is transformed into a Bernstein polynomial form. The basis function of the Bernstein polynomial is: Where n is the highest order; A certain dimension of the trajectory of a quadrotor drone based on the seventh-order Bezier curve can be expressed as: We choose to generate trajectories by setting the objective function to minimize Snap. For a certain dimension, we write the minimized objective function as: Using the derivative properties of the Bezier curve, the control points of each order of the UAV are defined. represents the l-th order derivative of the ith control point of the k-th trajectory of dimension λ, then It can be expressed as: Boundary constraints and continuity constraints are written in the form of equality constraints, safety constraints and multi-order dynamic feasibility constraints are written in the form of inequality constraints, and the trajectory generation problem is formulated as: A eq c=b eq s.t A ie c≤b ie c k ∈Ω k ,k=1,2,…,m Where c is the polynomial coefficient to be solved, which is a one-dimensional column vector composed of the polynomial coefficients of k segments of trajectory, and is also the control point of the UAV trajectory. k is the n control points in the flight corridor where the kth trajectory is located These control points are denoted as Ω k , which is solved in finite time using a convex solver.

4. The method for optimizing the trajectory of a UAV based on Bezier curves and flight corridors according to claim 1, characterized in that: In step 4), in the flight corridor design, factors of flight safety and environmental protection are taken into consideration, and the location and width of the flight corridor are marked on the map.

5. The method for optimizing the trajectory of an unmanned aerial vehicle based on Bezier curves and flight corridors according to claim 1, characterized in that: In step 6), in the real-time path tracking and control, the position and flight parameters of the UAV during flight are monitored in real time to ensure the accuracy and stability of the path, and the flight path is adjusted according to real-time environmental changes to ensure that the UAV can dynamically adapt to the needs of the flight mission.

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